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                谈笑风生                </h1>
                <p>时间限制：20s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：512MB</p>			</div>
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                                <h3>题目描述</h3><p><p><span style="font-size: medium">设T 为一棵有根树，我们做如下的定义：<br />
&bull; 设a和b为T 中的两个不同节点。如果a是b的祖先，那么称&ldquo;a比b不知道<br />
高明到哪里去了&rdquo;。<br />
&bull; 设a 和 b 为 T 中的两个不同节点。如果 a 与 b 在树上的距离不超过某个给定<br />
常数x，那么称&ldquo;a 与b 谈笑风生&rdquo;。<br />
给定一棵n个节点的有根树T，节点的编号为1 到 n，根节点为1号节点。你需<br />
要回答q 个询问，询问给定两个整数p和k，问有多少个有序三元组(a;b;c)满足：<br />
1. a、b和 c为 T 中三个不同的点，且 a为p 号节点；<br />
2. a和b 都比 c不知道高明到哪里去了；<br />
3. a和b 谈笑风生。这里谈笑风生中的常数为给定的 k。</span></p></p><hr/><h3>输入格式</h3><p><p><span style="font-size: medium">输入文件的第一行含有两个正整数n和q，分别代表有根树的点数与询问的个数。接下来n - 1行，每行描述一条树上的边。每行含有两个整数u和v，代表在节点u和v之间有一条边。<br />
接下来q行，每行描述一个操作。第i行含有两个整数，分别表示第i个询问的p和k。</span></p>
<p><span style="font-size: medium"><br />
</span></p>
<p></p></p><hr/><h3>输出格式</h3><p><p><font size="4">输出 q 行，每行对应一个询问，代表询问的答案。</font></p>
<p></p></p><hr/><h3>样例输入</h3><pre>5 3
1 2
1 3
2 4
4 5
2 2
4 1
2 3
</pre><hr/><h3>样例输出</h3><pre>
3
1
3
</pre><hr/><h3>提示</h3><p><p></p>
<p><span style="font-size: medium">1&lt;=P&lt;=N<br />
1&lt;=K&lt;=N<br />
N&lt;=300000<br />
Q&lt;=300000<br />
</span></p></p><hr/><h3>题目来源</h3><p>没有写明来源</p>
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